Re: [Discuss-gnuradio] RDS decoding ?

[Kevin McQuiggin]

Hi Jean-Michel and List:

As promised here is my RDS reception flowgraph.  It is based on a USRP device 
(I have a B200) so you may want to swap that for whatever device you are using. 
 I’ll leave it to you to develop the decoding program.  Mine is written in C, 
but you can use whatever you want.

Kevin

FM-RDS-v10-with-tcp.grc
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> On Jan 10, 2016, at 11:54 AM, Kevin McQuiggin <address@hidden> wrote:
> 
> Hi Jean-Michel:
> 
> Certainly!  It took me a couple of months of reading, experimentation and 
> head-scratching to figure the DSP side of RDS reception out.  I had a bit of 
> help from a couple of people on the [discuss-gnuradio] list as well.
> 
> The GRC is at home, I will post it to the list (or a pointer to it) when I 
> get back from my outing this morning.  I am a newbie though, so I am sure 
> that the experts on the list will find several improvements.
> 
> Like hardware radio, I find it very interesting that there can be several 
> “ways to do it” for a particular problem.
> 
> You will find that the next challenge, after you get the RDS data side 
> working, is to write the program that does the group detection, then frame 
> synchronization, error detection, and data extraction.  I wrote my program in 
> C, and it is about 1000 lines of code.  I started small and built it up from 
> there.  Currently it is working very well for several types of RDS frame.
> 
> I was in SE Asia on holiday for a few weeks with my wife and was able to use 
> the time to develop most of this code.  That’s MY kind of vacation!
> 
> I use a TCP Sink in GRC to deliver the RDS data from the flowgraph to the C 
> program.  The C program opens a socket and reads the data stream from it.  
> Terminal output is through the ncurses package.
> 
> You will need to read about the RDS spec both for the flowgraph (physical 
> layer) and for the data interpretation.  I used the official RDS/RBDS 
> specification document to develop my code.  I will send you a link to it as 
> well.
> 
> For this stage, I would recommend checking out the work done by Oona 
> Räisänen.  Her web site is http://www.windytan.com, and she has several 
> informative posts about RDS.
> 
> Kevin
> 
>> On Jan 10, 2016, at 4:45 AM, Jean-Michel FRIEDT <address@hidden> wrote:
>> 
>> I have just read on the gnuradio mailing list that you completed RDS
>> decoding. I too am stuck after extracting the 3*19 kHz carrier and mixing
>> with the original WBFM output to get the RDS stream at baseband. I am not 
>> sure
>> how to run the BPSK demodulator: would you mind sharing your grc graph so I
>> can also complete the demodulation ?
>> 
>> Thanks, Jean-Michel
>> 
>> --
>> JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe, 25000 
>> Besancon, France
>> 
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